Addition of the .creds extension to the credentials files generated by password lookup in order for Ansible not to consider them as inventory files with inventory_ignore_extensions set accordingly (#2446)

As requested

Ensure that kube-apiserver will respond even if one of the nodes are down.

Added CoreDNS to downloads

Updated with labels. Should now work without RBAC too

Fix DNS settings on hosts

Rename CoreDNS service from kube-dns to coredns

Add rotate based on http://edgeofsanity.net/rant/2017/12/20/systemd-resolved-is-broken.html

Updated docs with CoreDNS info

Added labels and fixed minor settings from official yaml file: https://github.com/kubernetes/kubernetes/blob/release-1.9/cluster/addons/dns/coredns.yaml.sed

Added a secondary deployment and secondary service ip. This is to mitigate dns timeouts and create high resitency for failures. See discussion at 'https://github.com/coreos/coreos-kubernetes/issues/641#issuecomment-281174806'

Set dns list correct. Thanks to @whereismyjetpack

Only download KubeDNS or CoreDNS if selected

Move dns cleanup to its own file and import tasks based on dns mode

Fix install of KubeDNS when dnsmask_kubedns mode is selected

Add new dns option coredns_dual for dual stack deployment. Added variable to configure replicas deployed. Updated docs for dual stack deployment. Removed rotate option in resolv.conf.

Run DNS manifests for CoreDNS and KubeDNS

Set skydns servers on dual stack deployment

Use only one template for CoreDNS dual deployment

Set correct cluster ip for the dns server

Flannel use interface for inter-host communication setted on --iface options
Defaults to the interface for the default route on the machine.

flannel config set via daemonset, and flannel config on all nodes is the same.
But different nodes can have different interface names for the inter-host communication network

The option --iface-regex allows the flannel to find the interface on which the address is set from the inter-host communication network

* Added option for encrypting secrets to etcd

* Fix keylength to 32

* Forgot the default

* Rename secrets.yaml to secrets_encryption.yaml

* Fix static path for secrets file to use ansible variable

* Rename secrets.yaml.j2 to secrets_encryption.yaml.j2

* Base64 encode the token

* Fixed merge error

* Changed path to credentials dir

* Update path to secrets file which is now readable inside the apiserver container. Set better file permissions

* Add encryption option to k8s-cluster.yml

Setting the following:

```
kube_kubeadm_controller_extra_args:
  address: 0.0.0.0
  terminated-pod-gc-threshold: "100"
```

Results in `terminated-pod-gc-threshold: 100` in the kubeadm config file. But it has to be a string to work.

1. 404 link url
2. kubelet_authentication_token_webhook is not work
3. kube_reserved variable set twice

Explicitly defines the --kubelet-preferred-address-types parameter #2418

Fixes #2453

details:https://github.com/moby/moby/pull/31490/files

Support docker-ce and docker-engine include redhat/centos ubuntu debian

Add `state: directory` to `file` task so that `recurse: yes` will actually take effect and ensure
certs/keys have the right file mode and owner

Change the name of `system:node` CRB to `kubespray:system:node` to avoid
conflicts with the auto-reconciled CRB also named `system:node`

Fixes #2121

Drain node except daemonsets resource
Use reset cluser for delete deploy data
Then delete node